In an Instagib match all players start with a Super Shock Rifle, a weapon that kills any enemy player with just one shot. All other weapons and ammo are removed from the game, as are pickups (sans specific items such as the Jump Boots), although players may still be equipped with a Translocator. The Super Shock Rifle cannot be dropped.
Instagib is typically used in the Deathmatch, Team Deathmatch, Domination, Double Domination, Capture the Flag, and Last Man Standing gametypes. It can be used in Invasion and Mutant, though the huge fire power defeats the challenge in defeating a superior force. It is not possible to use the official Instagib mutator in the Assault, Vehicle Capture the Flag, Onslaught, and Warfare gametypes, at least in a non-modded way.
In 2003/2004, there's a special variant of the Instagib mutator, called Zoom Instagib, whose alternate fire is a zoom function like that of the Lightning Gun. It's inspired by a third-party Unreal Tournament mutator of the same name.
- Arguably, this mutator has the biggest impact on gameplay of all official mutators.
- Because of the popularity of the combination Capture The Flag + Instagib + Low gravity + Team boosting, a later patch in Unreal Tournament 2004 adds the gametype Instagib CTF, with most of the required setups already in the options. The gamemode is also present in Unreal Tournament 3 and Unreal Tournament 4.